White light emission from Dy3+-doped LiLuF4 single crystal grown by Bridgman method

Lithium lutetium fluoride （LiLuF4） single crystals doped with different Dy3＋ ion concentrations were grown by Bridgman method. The Judd-Ofelt （J-O） strength parameters （Ω2, Ω4, Ω6） of Dy3＋ in LiLuF4 crystal are calculated according to the measured absorption spectra and the J-O theory, by which the asymmetry of the Dy3＋：LiLuF4 single crystal and the possibility of attaining stimulated emission from 4F9/2 level are analyzed. The capability of the Dy3＋：LiLuF4 crystal in generating white light by simultaneous blue and yellow emissions under excitation with ultra- violet light is produced. The effects of excitation wavelength and doping concentration on chromaticity coordinates and photoluminescence intensity are also investigated. Favorable CIE coordinates, x=0.319 3 and y=0.349 3, can be obtained for Dy3＋ ion in 2.701% molar doping concentration under excitation of 350 nm.     

碧护生态综合技术调控小麦生长作用研究

为明确碧护生态综合技术(0.136%赤·吲乙·芸苔WP、3%卵磷脂维生素E SE和含硅水溶肥料)在小麦上的应用效果,开展了田间试验。结果表明：碧护生态综合技术可明显提高小麦的抗逆性,冻害率降低至8.2%,芽麦率降低至1.53%,明显好于芸苔素内酯处理和常规对照处理;促进小麦生长,提高其对病虫害的防控能力,药后7、14 d对小麦蚜虫的防效分别达到96.19%和94.35%,较芸苔素内酯处理分别提高9.61%和9.90%,较常规对照分别提高15.53%和15.10%;药后14、21 d对小麦白粉病防效比常规对照增加40.65%和38.60%,药后21 d对小麦赤霉病的防效比常规对照增加41.81%;增产效果明显,较常规对照增产13.59%～18.16%,效果均优于芸苔素内酯处理。建议在小麦生产上应用碧护生态综合技术。     

Tunable emission,concentration quenching and crystallographic sites of Eu^2＋ in Sr3Y（PO4）3

A series of Sr3Y（PO4）3：Eu^2＋ samples are synthesized by the high temperature solid-state method. Sr3Y（PO4）3：Eu^2＋shows an asymmetrical emission band under excitation of 350 nm. The emission peaks at 426 nm and 497 nm are assigned to the nine-coordination Eu^2＋ and six-coordination Eu^2＋, respectively. The effects of Eu^2＋ doping content on the emission intensity and color are observed, and the concentration quenching effect is also observed. For two different Eu^2＋ luminescence centers, the quenching mechanisms are dipole-dipole interaction and quadrupole-quadrupole interaction, respectively. And the critical distance of energy transfer is calculated by concentration quenching and turns out to be about 3.67 nm. The results above show that the asymmetrical emission band of Sr3Y（PO4）3：Eu^2＋ comes from two different Eu2＋ luminescence centers in the lattice.     

轻烧磷酸砖的试验生产

以Al2O3≥80%的矾土熟料为主要原料,111米隧道窑窑车底部洞子低温烧成,制做K70牌号回转窑用轻烧磷酸砖,指标合格稳定,生产效率高。